Recorded matter having countermeasure against forging

ABSTRACT

An object is to provide a recorded article or sticker whereby counterfeited articles and genuine articles can be visually distinguished in simple fashion in the market and wherein it is not possible to identify in the market the location and type of the anti-counterfeiting measures that have been taken. Both an overt region  3  (which can be recognized visually in the market) are printing using a color-change ink or liquid-crystal ink, for example, and a covert region  5  formed by for example optical retro-reflective printing (which cannot be recognized without using a special tool) are provided on the surface of the same recording medium. The overt region  3  and the covert region  4  may be arranged at different locations or may overlap, or may be positionally aligned. The overt letter/design pattern and the covert letter/design pattern may be the same or different. An overt recording that is printed using liquid-crystal ink may also function as a covert recording by employing a genuineness inspection method using a circularly polarized plate. A sticker may be provided with one or a plurality of cuts such that the sticker is broken when peeled off, so that it cannot be re-used.

TECHNICAL FIELD

[0001] The present invention relates to a recorded article such as forexample a printed article, with anti-counterfeit measures.

BACKGROUND ART

[0002] In order to prevent counterfeiting of recorded articles such asfor example printed articles produced by color copying technology usingan optical image scanner and color printer or in order to ascertaingenuineness by identifying whether a subject article is a forgery or agenuine article, recording or printing techniques are known in whichspecial optical characteristics are applied to the surface of theprinted article. Such recording techniques for preventing counterfeitingcan be classified into two types, called overt and covert. The specialoptical characteristics of the overt technique are exposed i.e. can beidentified simply by directly viewing with the naked eye under naturallight. The special optical characteristics of the covert technique arehidden and can only be identified by viewing under special opticalconditions or using special optical tools.

[0003] A typical example of an overt technique is recording or printingusing a color-change ink; this is disclosed in Laid-open Japanese PatentPublication No. H8-324169 or Laid-open Japanese Patent Publication No.H9-254520 or Laid-open Japanese Patent Publication No. H10-060303. Acolor-change ink has the property that the main wavelength of reflectedlight therefrom when white light is directed on to the surface of theink changes depending on the angle of incidence (angle of reflection).The perceived color of a surface printed with a color-change inktherefore changes when the angle of viewing is changed.

[0004] A typical example of a covert technique is recording or printingaccompanied by surface processing to produce optical retroreflectionproperties, as disclosed in U.S. Pat. No. 2,407,608 or Laid-openJapanese Patent Publication No. H10-97308, for example. Opticalretroreflection means a reflection characteristic whereby the angle ofincidence and the angle of reflection are substantially the same i.e. areflection characteristic in which incident light is bent back so thatthe reflected light is returned to the light source. A covertly recordedportion having optical retroreflection is of exactly the same color asthe surrounding region when viewed under natural light and so cannot bedistinguished, but can be distinguished from the surrounding region whenviewed using a special tool.

[0005] Since both overt techniques and covert techniques require specialinks or special processes for processing, a recorded articlemanufactured using such techniques cannot be reproduced using a simplecolor copier.

[0006] A recorded article to which an overt technique has been appliedand a counterfeit article manufactured by simply copying this using acolor copier can be differentiated visually simply by ordinary viewingunder natural light. Accordingly, even supposing such a simplecounterfeit product appears on the market, people in the market caneasily notice that it is not a genuine product. The effectiveness ofovert techniques in excluding simple counterfeit products from themarket is therefore high. Other hand, since the location and type ofsuch overt recording on the article in question are apparent to the eyesof anyone, this gives a clue to other persons intending to imitate suchovert recording.

[0007] In contrast, the presence of covert recording cannot be noticedby people in the market. There is therefore little likelihood of cluesto imitate this covert recording being given to other persons. However,people in the market cannot normally identify the presence of covertrecording, so there is a high probability of people in the market beingsimply cheated even by simple counterfeit articles.

DISCLOSURE OF THE INVENTION

[0008] An object of the present invention is therefore to provide arecorded article or printed article with anti-counterfeiting measureswhereby counterfeited articles and genuine articles can be visuallydistinguished in simple fashion in the market and wherein it is notpossible to identify in simple fashion in the market the location andtype of the anti-counterfeiting measures that have been taken.

[0009] A further object of the present invention is to provide asecurity label in the form of a label or sticker suitable for stickingonto for example products or product packaging, that can be employed forpreventing counterfeiting of products or for ascertaining genuineness.

[0010] A recorded article according to one aspect of the presentinvention comprises an overt recording formed by an overt technique anda covert recording formed by a covert technique on the surface of thesame recorded medium. With this recorded article, genuineness can beascertained in simple fashion even in the market by means of the overtrecording and, even if counterfeit products appear imitating the overtrecording, genuineness can still be ascertained using the covertrecording. Also, a synergetic effect of the overt and covert recordingsis obtained in that the presence of the overt recording in this recordedarticle acts as a decoy making it difficult to notice the presence ofthe covert recording.

[0011] In a recorded article according to the present invention, it canbe arranged that the overt recording and covert recording at leastpartially overlap. It can also be arranged to make the overt recordingand covert recording of different plan design in regard to for exampletheir shape or size. Such an arrangement makes counterfeiting even moredifficult.

[0012] The overt recording may be made extremely difficult tocounterfeit by forming by for example superimposing liquid-crystal inkon a color-change ink.

[0013] Also, when the overt recording and covert recording aresuperimposed, the covert recording may be formed by an opticalretroreflection layer comprising minute transparent spheres arranged ona transparent reflecting layer. With such a construction, under naturallight, the covert recording is substantially transparent or close totransparent and the overt recording therebelow can be clearly seen. Whenviewed under special conditions or using a special tool, the covertrecording can be clearly seen.

[0014] The overt recording and covert recording can also be stacked inperfect alignment by making their plan design such as shape and sizecompletely identical. If this is done, an even more effective decoyeffect of the overt recording may be exhibited.

[0015] Also, the overt recording may be formed by superimposingliquid-crystal ink on an underlayer of a specified color, orsuperimposing a background region around the overt recording orsuperimposing liquid-crystal ink on an underlayer of different color, ormay also be formed by directly employing an underlayer of the abovespecified color, without superimposing liquid-crystal ink thereon. Inthis way, the overt recording can also function as a covert recording.

[0016] In this way, ascertaining genuineness can be performed using thecovert recording function, by observing this recorded article, on whicha recording has been formed that functions both as an overt recordingand a covert recording, using liquid-crystal ink, through for example aclockwise circularly polarized plate and anticlockwise circularlypolarized plate, respectively.

[0017] A security label according to a further aspect of the presentinvention comprises an overt recording formed by an overt technique anda covert recording formed by a covert technique on the surface of asingle recording medium and further comprises an adhesive layer wherebythe security label can be stuck onto a subject article such as a productor product packaging. The overt recording is capable of producing colorchange depending on the angle of observation by selective reflection oflight. The covert recording is capable of being identified by means of aspecial tool or device.

[0018] Alternatively, the overt recording may be produced using aliquid-crystal material or may be produced using a material obtained bylaminating a metallic oxide layer and/or metal and thin-film mica glasslayer and/or silicon oxide.

[0019] Alternatively, the covert recording may contain a material thatreflects or transmits light of a specified spectral pattern with respectto infra-red light, so as to enable the genuineness thereof to beascertained by comparing the spectral pattern of the light that isreflected or the light that is transmitted in respect of illuminationwith infra-red light with a spectral pattern that has been storedbeforehand in a specified tool or device.

[0020] Also, the area of this security label may be no more than 8square centimeters.

[0021] Furthermore, the security label may be provided with a cut at oneor a plurality of locations such that, if an attempt is made to peel offthe security label once it has been a fixed to a subject article, thesecurity label is broken and rendered incapable of re-use.

[0022] As the method of manufacturing a security label according to thepresent invention, an overt recording may be printed by an overttechnique and a covert recording may be printed by a covert techniqueprinting on the surface of the same recording medium; the overttechnique may be a silkscreen method.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1A and FIG. 1B are diagrams of a recording surface printedwith a color-change ink using an overt technique;

[0024]FIG. 2 is a plan view showing the plan design of major parts of anembodiment of a recorded article according to the present invention;

[0025]FIG. 3 is a plan view showing the plan design of major parts ofanother embodiment;

[0026]FIG. 4 is a plan view showing the plan design of major parts of afurther embodiment;

[0027]FIG. 5 is a plan view showing the plan design of major parts ofyet a further embodiment;

[0028]FIG. 6 is a cross-sectional view showing an example of theconstruction of a base portion of the cross-section, (for example,cross-section along the line A-A of FIG. 2) of an overt region 3 of theprinted article shown in FIG. 2 or FIG. 3;

[0029]FIG. 7 is a cross-sectional view showing an example of theconstruction of a base portion of the cross-section, (for example,cross-section along the line B-B of FIG. 2) of a covert region 5 of theprinted article shown in FIG. 2 or FIG. 3;

[0030]FIG. 8 is a cross-sectional view showing a further example of theconstruction of the cross-section of an overt region 3 of the printedarticle shown in FIG. 2 or FIG. 3;

[0031]FIG. 9 is a cross-sectional view showing yet a further example ofthe construction of the cross-section of an overt region 3 of theprinted article shown in FIG. 2 or FIG. 3;

[0032]FIG. 10 is a cross-sectional view showing the appearance when theovert recording formed using the liquid-crystal ink shown in FIG. 8 andFIG. 9 is observed through a circularly polarized plate that transmitsanticlockwise polarized light;

[0033]FIG. 11 is a cross-sectional view showing the appearance when theovert recording formed using the liquid-crystal ink shown in FIG. 8 andFIG. 9 is observed through a circularly polarized plate that transmitsclockwise polarized light;

[0034]FIG. 12 is a cross-sectional view showing an example of theconstruction of a base portion of the cross-section of a region wherethe overt region and covert region shown in FIG. 3 to FIG. 5 aresuperimposed (for example the cross-section along C-C shown in FIG. 3);

[0035]FIG. 13 is a cross-sectional view showing a further example of theconstruction of the cross-section of a region where the overt region andcovert region shown in FIG. 3 to FIG. 5 are superimposed;

[0036]FIG. 14 is a plan view of an embodiment of a security labelaccording to the present invention;

[0037]FIG. 15 is a plan view of a further embodiment of a security labelaccording to the present invention;

[0038]FIG. 16 is a plan view of yet a further embodiment of a securitylabel according to the present invention; and

[0039]FIG. 17 is a plan view of yet a further embodiment of a securitylabel according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0040] Embodiments of the present invention are described below.

[0041] In these embodiments, in each case, an overt recording(hereinbelow, simply referred to as an “overt”) formed by an overttechnique and a covert recording (hereinbelow, simply referred to as a“covert”) formed by a covert technique are provided on the surface ofthe same recording medium. For the overt recording, for examplerecording is employed that produces a color change depending on theangle of observation by selective reflection of light (hereinbelowturned “color-change recording”).

[0042] Specifically, as a material that forms selective reflection oflight, there may be mentioned by way of example a liquid-crystalmaterial or a material obtained by laminating a metallic oxide layer,metal, mica glass or silicon oxide or other material. The desired objectcan be achieved by preparing such a material as a printing ink andperforming printing therewith. Some description will now be givenconcerning selective reflection.

[0043] A liquid-crystal material (in particular a cholestericliquid-crystal) has a structure in which the molecular arrangement istwisted little by little along the helical axis, so that theliquid-crystal as a whole forms a helical structure. As is well known,such a structure provides properties such as optical rotatory power,selective optical scattering and circular polarization dichroism.Specific examples of such materials include the BASF PALIOCOLOR(registered trademark) series. Also, a material produced by laminating ametallic oxide layer, metal, mica glass and silicon oxide (hereinbelowturned optical brightness pigment) reflects light of differentwavelengths depending on the angle, due to the different refractiveindices of the laminated substances and so appears to human eyes asdisplaying color changes. Specifically, it indicates a material obtainedby grinding to a suitable size a pigment formed by laminating metallicoxide such as silicon oxide, titanium oxide, aluminum oxide or ironoxide with a base material of low transparency such as thin flakes ofmica or a material obtained by grinding to a suitable size a materialobtained by laminating silica and a layer that reflects light, such as ametal or a metallic oxide. A specific example thereof is PALIOCROMpigment (BASF trademark) or other materials. An ink of appropriatephysical properties or performance is prepared by combining any of thesematerials in a manufacturing device (printing device).

[0044]FIG. 1 is a diagram of a color-change ink recording surface.

[0045] A color-change ink can be printed by ordinary printing methods.As shown in FIG. 1A, preferably the liquid-crystal material or opticalbrightness pigment employed in the color-change ink consists in flatplate shapes of pigment 100 arranged in a regular attitude on thesurface of a recording medium 200 for recording. As shown in FIG. 1A, byarranging the flat shapes of pigment 100 in a regular fashion, the angleof reflection of the reflected light 400 with respect to the angle ofincidence of the incoming light 300 can be maintained constant. In thisway, a large color change of the color-change recording can be produced,which is desirable for an overt recording. In contrast, as shown in FIG.1B, if the flat plate shapes of pigment 100 are irregularly arranged onthe surface of the recording medium 200, the reflected light 600 isreflected with scattered angles (scattered reflection) with respect to aparallel incident beam 500. With a recording surface in such acondition, the desired excellent color-change characteristic cannot beobtained.

[0046] The magnitude of the color change was described with reference tothe diagrams are FIG. 1A and FIG. 1B, but when the recording surface ofan actual color-change recording is observed, it is found that thecondition of arrangement of the pigment is different depending on themethod of printing. For example, it has been found that a method ofprinting using the silkscreen method is suitable for an arrangement ofthe flat plate shapes of pigment 100 approaching the condition of FIG.1A.

[0047] On the other hand, in the case of a covert recording, therecording cannot be recognized solely by the naked eye under sunlight orordinary illumination and may be adopted where recording is to beperformed by a special recording method such that the recording can onlybe recognized using special equipment.

[0048] Specific examples that may be given include fluorescent ink orphosphorescent ink. Commercially available inks of this type may beemployed. Typically, with such inks, the recording pattern emits lightand may be observed by irradiating with ultraviolet light. Forirradiating with ultraviolet light, for example a “black lamp” may beemployed. Since the recording pattern does not emit light under sunlightor light from fluorescent lamps, it cannot be read. Such an ink may beused for printing at a position separate from the recording position ofthe ink used in the overt technique. Another type of covert recordingthat may be mentioned by way of example is recording using a recordingmethod that produces optical retroreflection. One method of recording toproduce optical retroreflection is for example to form a transparentreflective layer of a specified pattern in a given region and to spreadinnumerable minute transparent spheres thereon, covering this region. Acovert recording (pattern of the reflective layer) recorded by such amethod of producing optical retroreflection cannot be recognizedvisually under natural light, but can be seen if viewed for examplethrough optical equipment capable of illuminating it with intense lightfrom the same direction as the line of vision.

[0049] As a further covert recording technique, a recording techniquemay be employed such that the spectral waveform of the intensity (oroptical reflectance, optical transmittance or optical absorbancethereof) of the reflected light or transmitted light therefrom whenspecified light is directed on to the covert recording is a specifiedwaveform. For example, a covert recording may be employed in whichrecording is effected using ink containing infra-red absorbing(reflecting) material having a high absorbance (or reflectance)specifically in regard to infra-red light of wavelength of 650 nm ormore. By employing such an infra-red absorbing (reflecting) ink, thegenuineness of a subject article can be ascertained by comparing thespectral pattern of light reflected from the subject article onirradiation with infra-red light with the correct spectral pattern ofreflected light of this infra-red absorbing (reflecting) ink, which hasbeen stored beforehand in the inspection device. With this method ofinspection, the spectral pattern of the reflected light produced byinfra-red light of the infra-red absorbing (reflecting) ink is storedbeforehand in the inspection device and, if it is ascertained that thespectral pattern of the reflected light from the subject article isdifferent from the spectral pattern of the reflected light stored in theinspection device, the subject article is deemed to be a counterfeitarticle whereas, if it is ascertained that the spectral pattern of thereflected light from the subject article is the same as the spectralpattern of the reflected light stored in the inspection device, thesubject article is deemed to be a genuine article. In order tofacilitate inspection, infra-red reflecting (reflecting) ink asdescribed above may be included in the recorded portion recorded withthe overt recording technique.

[0050]FIG. 2 to FIG. 4 respectively show the plan design of major partsof three embodiments of a recorded article according to the presentinvention.

[0051] In the recorded articles 1A, 1B, 1C of FIG. 2 to FIG. 4, both anovert recording region 3 recorded using an overt technique and a covertregion 5 recorded by a covert technique are provided on the surface ofthe same recording medium. In the case of the recorded article 1A ofFIG. 2, the overt region 3 and covert region 5 are arranged in separate,non-overlapping locations. In the case of the recorded article 1B ofFIG. 3, the overt region 3 and covert region 5 partially overlap. In thecase of the recorded article 1C of FIG. 4, the overt region 3 and covertregion 5 are stacked so as to be positionally aligned. Although notshown in the drawings, it is also possible to arrange one of the overtregion 3 and covert region 5 so as to include the other.

[0052] In the overt regions 3 shown in FIG. 2 to FIG. 4, letters, forexample “PRINT” are printed using for example a color-change ink so asto have a special optical characteristic for the overt recording. Thebackground region other than the letters “PRINT” in the overt recordingregion 3 may be without the special optical characteristic for the overtrecording or may be printed for example using a color-change ink of adifferent color, to provide another type of overt recording, which canbe differentiated from “PRINT” when viewed. Also, conversely, only thebackground region, excluding the letters “PRINT” may be printed so as tohave the special optical characteristic for the overt recording.

[0053] Consequently, it can be seen that the letters “PRINT” or thebackground in the overt region 3 have a special optical characteristic,for example the property that their perceived color changes depending onviewing angle, simply by viewing with the naked eye under natural light.

[0054] In contrast, in the covert region 5, for example the letters“GENUINE” are printed so as to have a special optical characteristic,for example optical retroreflection, for covert recording. Thebackground region other than the letters “GENUINE” in the covertrecording region 5 may be without the special optical characteristic forthe covert recording. Also, conversely, only the background region,excluding the letters “GENUINE” may be printed so as to have the specialoptical characteristic for the covert recording. Whichever method isadopted, simply by viewing with the naked eye under natural light, thebackground region appears the same as the letters “GENUINE”, so theletters “GENUINE” cannot be read.

[0055] The letters “GENUINE” in the covert region 5 can therefore beread only when viewed under special optical conditions or using aspecial tool; for example in the case of optical retroreflection, theletters can only be viewed when illuminated with light that is moreintense than the background light, from the same direction as the lineof view.

[0056] Furthermore, the covert region 5 and the background region 7around the outside of this appear the same when viewed merely with thenaked eye under natural light, so these two cannot be distinguished. Itis therefore normally not possible to tell whether or not a covertregion 5 is present on the recorded article 1 and where it is present onthe recorded article 1.

[0057] In the recorded article having both overt and covert recordingsshown in FIG. 2 to FIG. 4, genuineness can be ascertained in a simplemanner even in the market, using the overt recording but even ifcounterfeit articles should appear imitating even the overt recording,genuineness can still be ascertained using the covert recording.

[0058] In addition, the presence of the overt recording acts as a decoyto the counterfeiter, hiding the presence of the covert recording evenmore effectively i.e. the overt and covert recordings may be regarded ashaving a synergetic effect. That is, there is a stronger probabilitythan in the case of prior art articles, in which only a covert recordingis employed on its own, that the counterfeiter, noticing the presence ofthe overt recording, may not anticipate the presence of a covertrecording and may therefore be neglectful of efforts to search for acovert recording.

[0059] Furthermore, the presence of both overt and covert recordingstogether on the same recorded article makes counterfeiting itselfextremely difficult. Specifically, in fact, in the case of both overtand covert recordings, even when these are employed alone, special inksor special methods of manufacture are necessary in order to imitatethese exactly, so this is not easy because of the high cost. In thesecircumstances, the presence of both overt and covert recordings on thesame recorded article requires an even more complex and high-cost methodof manufacture, so counterfeiting to produce an exact imitation isextremely difficult. In particular, when, as shown in FIG. 3 and FIG. 4,the overt and covert recordings overlap, in this overlapping portion,the optical characteristics of both the overt and covert recordings actin combination, so elucidation of the materials and/or structure of thisportion is extremely difficult for the counterfeiter; even if thecounterfeiter knows these, it is difficult to achieve the same colortone or optical conditions, so, as a result, an exact imitation is verydifficult.

[0060] The plan design (i.e. the external shape and size of the regionsthemselves and the shape, size and arrangement and other particulars ofthe letters or designs recorded in the regions) of the overt region 3and covert region 5 shown in FIG. 2 to FIG. 4 can be freely determined.However, in a preferred embodiment, as in the examples of FIG. 2 to FIG.4, the patterns of the overt region 3 and covert region 5 are differentin regard to for example the size or type or arrangement of the lettersor designs. Such differences of pattern make manufacture of acounterfeited articles difficult due to the added complexity.

[0061] Furthermore, regarding the arrangement of the covert region 3 andcovert region 5, if these two regions are superimposed as describedabove, the advantage is obtained that the method of manufacturingcounterfeits becomes extremely difficult. On the other hand, if theovert region 3 and the covert region 5 are arranged in completelydifferent locations, the advantage is obtained that it is difficult todiscover the covert recording. In particular, if for example the overtrecording is a large striking pattern whereas the covert recording is asmall pattern arranged in a location that cannot easily be discovered,the decoy effect of the covert recording is exhibited to even moreadvantage, so that the covert recording is even more difficult todiscover.

[0062] Furthermore, a plurality of variations in regard to thearrangement and/or patterns of the overt and covert recordings describedabove may be employed in suitable combination, thereby further improvingdifficulty of counterfeiting.

[0063]FIG. 5 shows a plan design of major parts of another embodiment ofa recorded article according to the present invention.

[0064] In the recorded article 11 shown in FIG. 5, an overt region 13and covert region 15 having exactly the same plan design are made to bealigned in position. Specifically, in these regions 13 and 15, forexample the letters “PRINT” have the special optical characteristics ofthe overt recording and also have the special optical characteristics ofthe covert recording, while the background area apart from the letters“PRINT” does not have these special optical characteristics or,conversely, only the background area, excluding the letters “PRINT” hasboth of the special optical characteristics of the overt and covertrecordings. Alternatively, the letters “PRINT” may have the specialoptical characteristics of the overt recording while the background areahas the special optical characteristics of the covert recording; orconversely.

[0065] In this way, even when overt and covert recordings of the sameplan design are aligned in position, the decoy effect of the overtrecording is effectively exhibited, hiding the presence of the covertrecording. That is, there is a high probability that the counterfeiterwill assume that the overt region 13 consists solely of an overtrecording and will not expect this to be combined with a covertrecording. As a modified example, the overt and covert recordings of thesame plan design may overlap, but shifted by a slight distance (forexample a distance smaller than the line thickness of the letters), orovert and covert recordings of similar plan designs differing somewhatin size may be stacked in a concentric positional relationship.

[0066]FIG. 6 shows an example of the structure of the base portion ofthe cross-section (for example the cross-section A-A of FIG. 2) of anovert region 3 of the recorded article shown in FIG. 2 or FIG. 3.

[0067] As shown in FIG. 6, the pattern of letters or design of the overtrecording (for example “PRINT”) is printed with color-change ink 23 onthe upper surface of the base 21. For the color-change ink 23, there maybe employed for example a color-change ink obtained by mixing flatpigment shapes 25 comprising for example a liquid-crystal material oroptical brightness pigment with ordinary ink. Printing using thecolor-change ink 23 may be performed by a special printing method inwhich the surface directions of the surfaces 25 of the flat pigmentshapes are aligned, for example by the silkscreen method.

[0068] Light which is incident onto the surface of the color-change ink23 exits as reflected light that is reflected by the internal flatpigment shapes 25. When this happens, specified wavelengths areselectively emphasized by interference of the reflected light at theupper surface and the reflected light at the lower surface of the flatpigment shapes 25. The wavelengths that are emphasized change dependingon the angle of incidence. Accordingly, as shown in FIG. 6, when forexample beams of white light 27, 31 are incident at different angles ofincidence, the respective reflected beams 29 and 33 appear to havedifferent colors. Consequently, the area that is printed with thecolor-change ink 23 appears in a different color depending on the angleof view. In contrast, the reflected beams 37, 41 of the white lightbeams 35 and 39 that are incident on areas that have not been speciallyprinted in this way are all of the same color, so there is no colorchange depending on angle of view.

[0069]FIG. 7 shows an example of the structure of the base portion ofthe cross-section (for example, cross-section along the line B-B of FIG.2) of the covert region 5 of the recorded article shown in FIG. 2 orFIG. 3.

[0070] The example shown in FIG. 7 is an example in which a covertrecording is constituted by a recording method in which opticalretroreflection is conferred thereon. As shown in FIG. 7, a transparentreflective layer 43 is formed with letters or a design pattern (forexample, “GENUINE”) of the covert recording on the upper surface of thebase 21. On top of this, innumerable minute transparent spheres 45 arespread so as to cover the entire covert region 5 and are then fixed byan adhesive layer 47.

[0071] Part of the upper surface below the minute spheres 45 above thereflective layer 43 is covered by a reflective layer 43. By selection ofthe material of the reflective layer 42, minute spheres 45 and adhesivelayer 47, reflection of light that has passed through the interior ofthe minute spheres 45 at the upper surface where the minute spheres 45are in contact with the reflective layer 43 may be facilitated or, onthe other hand, substantially all of the light that has passed throughthe interior of the minute spheres 45 may be arranged to exit to outsidethe minute spheres 45 without being reflected at the surface where theminute spheres 45 make contact with the adhesive layer 43.

[0072] When light is incident on a covert region 5 constructed in thisway, the light 49 that is incident on the region where the reflectivelayer 43 is present enters the minute spheres 45, so part thereof isreflected at the surface of the minute spheres 45, producingretroreflection light 51 that returns in the direction of the incidentlight 49. Part of the remainder of the incident light 49 is reflected atthe surface of the base 21 after exiting to the minute spheres 45 andexits in a direction (diffuse reflected light 53) completely differentfrom that of the incident light 49. Also, the light 55 that is incidentin the region where the reflective layer 43 is not present enters theminute spheres 45, so substantially all of this light is reflected atthe surface of the base 21 after exiting the minute spheres 45 and exitsin a direction completely different from that of the incident light 55(diffuse reflected light 59).

[0073] Consequently, under natural light that is incident withsubstantially the same intensity from all directions, theretro-reflected light 51 does not stand out, since it is mixed withother diffuse reflected light, so the covert recording cannot berecognized with the naked eye. However, if the covert region 5 isilluminated with intense light from the same direction as the line ofvision, the amount of light of the retro-reflected light 51 becomeslarger than the diffuse reflected light 53, so the covert recording canbe seen.

[0074]FIG. 8 shows an example of another structure of the cross-sectionof the overt region 3 of the recorded article shown in FIG. 2 or FIG. 3.

[0075] In the example shown in FIG. 8, an overt recording is formedusing liquid-crystal ink. As shown in FIG. 8, letters or a designpattern (for example “PRINT”) of the overt recording are printed with aspecified ink 61 on the upper surface of the base 21. On top of this,liquid-crystal ink 63 having circular polarization dichroism is used tocoat the entire overt region 3. As the specified ink 61, an ordinarycolored ink may be employed, or a color-change ink as described abovemay be employed or a liquid-crystal ink may be employed (in this case,the liquid-crystal ink is laminated). As the liquid-crystal ink 63, acholesteric liquid-crystal ink (for example BASF's PALIOCOLOR(registered trademark)) having optical properties such as opticalrotator power, selective optical scattering and circular polarizationdichroism may be employed.

[0076] When light is incident on an overt region 3 constituted in thisway, the light 65 that is incident on the region of the specified ink 61is divided into two circularly polarized beams, anticlockwise beam 67and clockwise beam 69, by the circular polarization dichroism of theliquid-crystal ink 63; the anticlockwise beam 67 is reflected by theliquid-crystal ink 63, while the clockwise beam 69 is transmittedthrough the liquid-crystal ink 63. When the clockwise beam 69 that hasthus been transmitted is incident on the specified ink 61, part thereof71 is absorbed while the remaining part (having the color of thespecified ink 61) 73 is reflected. Consequently, the color obtained bycombining the anticlockwise beam 67 reflected by the liquid-crystal ink63 and the clockwise beam 73 reflected by the specified ink 61 isobservable by human beings.

[0077] In contrast, in the region where no specified ink 61 is present,the light 75 that is incident in the region where for example the base21 can be seen is split into two circularly polarized beams,anticlockwise beam 77 and clockwise beam 79, in the same way asdescribed above, due to the circular polarization dichroism of theliquid-crystal ink 63, the anticlockwise beam 77 being reflected by theliquid-crystal ink 63 and the clockwise beam 79 being transmittedthrough the liquid-crystal ink 63. The transmitted clockwise beam 79 isincident on the base 21, where part thereof 81 is absorbed and theremaining part (having the color of the base 21) 83 is reflected.Consequently, the color obtained by combining the anticlockwise beam 77reflected by the liquid-crystal ink 63 and the clockwise beam 73reflected by the base 21 is observable by human beings.

[0078] Since the color of the specified ink 63 and the color of the base21 are different, the color that is observed by human beings isdifferent in the region of the specified ink 63 and of the base 21.Furthermore, this observed color is not a simple color but rather is acolor having a special optical effect due to the action of theliquid-crystal ink 63. For example, if the specified ink 63 is black, arainbow-colored effect appears in the color that is seen. Also, if thespecified ink 63 is a color-change ink, the color that is seen is tingedwith this color-change effect. Also, if the specified ink 63 is aliquid-crystal ink, a mirror effect appears. On the other hand, if thebase 21 is for example white, a pearl color effect appears in the colorthat is seen. In all cases, the color having a special effect obtainedby the liquid-crystal ink 63 cannot be reproduced by a simple colorcopier.

[0079]FIG. 9 is yet a further example construction of the cross-sectionof the overt region 3 of the recorded article shown in FIG. 2 of FIG. 3.

[0080] The example of FIG. 9 is also an example in which an overtrecording is formed using liquid-crystal ink. As shown in FIG. 9, firstof all, a coating of the specified ink 61 is applied to the entire overtregion 3 on the upper surface of the base 21. On top of this, an overtpattern of for example letters or a design (for example “PRINT”) isprinted with liquid-crystal ink 63 having circular polarizationdichroism.

[0081] When light is incident onto the overt region 3 constructed asabove, in the region printed with the liquid-crystal ink 63, as alreadydescribed, a color having a special effect obtained by combining theanticlockwise beam 67 reflected by the liquid-crystal ink 63 and theclockwise beam 73 reflected by the specified ink 61 is observed by humanbeings. In contrast, in the region where there is no liquid-crystal ink63, reflected light 67 of the color of the specified ink 61 is observed.

[0082] It should be noted that the construction shown in FIG. 8 and theconstruction shown in FIG. 9 could be combined. Specifically, an overtregion could be designed by combining three types of pattern, namely, apattern printed by overlaying a liquid-crystal ink 63 onto the specifiedink 61, a pattern in which printing is effected only with the specifiedink 61 and a pattern printed with the liquid-crystal ink 63 overlayingthe base 21.

[0083] Furthermore, the overt recording formed using the liquid-crystalink shown in FIG. 8 and FIG. 9 also has the function of a covertrecording, due to the circular polarization dichroism possessed by theliquid-crystal ink. This will be described with reference to FIG. 10 andFIG. 11.

[0084]FIG. 10 describes the appearance of an overt region formed usingliquid-crystal ink 63 when viewed through an anticlockwise circularpolarization plate 101 that selectively transmits anticlockwise light.FIG. 11 shows the appearance of an overt region formed usingliquid-crystal ink 63 when viewed through a clockwise circularpolarization plate 103 that selectively transmits clockwise light.

[0085] As shown in FIG. 10, when viewed through the anticlockwisecircular polarization plate 101, of the reflected beams 67, 73, 77, 83incoming from the region coated with liquid-crystal ink 63, only theanticlockwise beams 67 and 77 reflected by the liquid-crystal ink 63 areobserved on passage through the anticlockwise circular polarizationplate 101. Consequently, the region coated with the liquid-crystal ink63 appears in the same color irrespective of the optical characteristicsof the underlying layer (for example whether this consists of thespecified ink 61 or the base 21). That is, the pattern that is printedwith the specified ink 61 in the region coated with the liquid-crystalink 63 cannot be seen. However, the region that is coated with theliquid-crystal ink 63 and the region that is not thus coated (regionwhere the reflected light 87 is directly incoming from the specified ink61) can be distinguished by different colors.

[0086] Contrast, as shown in FIG. 11, when viewed through the clockwisecircular polarization plate 103, of the reflected beams 67, 73, 77, 83incoming from the region coated with the liquid-crystal ink 63, only theclockwise beams 73 and 83 that are reflected by the underlayer afterpassing through the liquid-crystal ink 63 are observed through theanticlockwise circular polarization plate 103. Consequently, in theregion coated with the liquid-crystal ink 63, the pattern printed withthe specified ink 61 and the pattern which is not thus printed can beclearly distinguished. However, the pattern of the specified ink 61 thatis coated with the liquid-crystal ink 63 and the pattern of thespecified ink 61 that is not thus coated appear with the same colorthrough the clockwise polarization plate 103 and so cannot bedistinguished.

[0087] Thus, when the overt region in which the liquid-crystal ink wasemployed is observed using the circular polarization plates, a differentappearance is presented to that seen simply with the naked eye.Consequently, even if a counterfeiter has imitated by another method thecovert region using the liquid-crystal ink (it is in fact possible toproduce a rainbow-colored effect or pearl colored effect and the likesimilar to that of a liquid-crystal ink by other methods), the fact thatthe article is counterfeit can still be ascertained by observation usinga circularly polarized plate. In this respect, the overt recording usingthe liquid-crystal ink also provides the function of a covert recording.For example, if a pattern as shown in FIG. 5 is manufactured usingliquid-crystal ink, it can naturally be manufactured in overt form andcovert form.

[0088] A circularly polarized plate can be created for example asfollows. Specifically, a PVA film or the like is uniaxially extended anddyed with iodine. If required, dyeing may be performed with anothermaterial of desired color. In addition, a protective layer is applied toprevent the iodine escaping. A circularly polarized plate is created bysuperimposing a ¼ wavelength film and the above film. The distinctionbetween clockwise polarization and anticlockwise polarization plates isachieved by sticking on a linearly polarized plate and a ¼ wavelengthfilm at an angle offset by 45° with respect to the axis of linearpolarization.

[0089]FIG. 12 shows an example of the structure of the base portion ofthe cross-section (for example, cross-section along C-C shown in FIG. 3)of a region where the overt regions 3, 13 shown in FIG. 3 to FIG. 5 andthe covert regions 5, 15 overlap.

[0090] As shown in FIG. 12, first of all, an overt letter or designpattern is printed with color-change ink 23 on the surface of the base21. On top of this, a covert letter or design pattern is formed by areflective layer 43. On top of this, innumerable minute spheres 45 arespread so as to cover the entire covert region, and fixed by means of anadhesive layer 47.

[0091] With such a region of overlapping overt and covert recordingsconstructed in this way, the retro-reflected light produced by theminute spheres 45 and reflective layer 43 is not noticeable undernatural light, so only the overt recording produced by the color-changeink 23 can be recognized; this appears to change in color depending onthe angle of view. However, when this is illuminated with intense lightfrom the same direction as the line of view, the intensity of theretro-reflected light described above is relatively increased, with theresult that the covert recording also becomes visible.

[0092]FIG. 13 shows another example of the construction of thecross-section of a region (for example, a cross-section along C-C shownin FIG. 3) where the overt and covert recordings shown in FIG. 3 andFIG. 5 overlap.

[0093] As shown in FIG. 13, first of all, an overt pattern constitutedfor example by letters or designs is printed with a specified ink 61(usually, for example, colored ink, color-change ink or liquid-crystalink) on the surface of the base 21. On top of this, the entire overtregion is coated with liquid-crystal ink 63. On top of this, a covertletter or design pattern is formed by a reflective layer 43. On top ofthis, innumerable minute spheres 45 are spread so as to cover the entirecovert region, and fixed by means of an adhesive layer 47.

[0094] With such a region of overlapping overt and covert recordingsconstructed in this way, the retro-reflected light produced by theminute spheres 45 and reflective layer 43 is not noticeable undernatural light, so the overt recording (pattern printed with thespecified ink 61) covering the liquid-crystal ink 63 is seen with acolor having a special optical effect. When illuminated with intenselight from the same direction as the line of view, the intensity of theretro-reflected light described above is relatively increased, with theresult that the covert recording (pattern of the reflective layer 43)also becomes visible.

[0095]FIG. 14 to FIG. 17 show respectively plan views of differentembodiments of a security label according to the present invention.

[0096] The security labels are stickers having an adhesive layer on oneface thereof and are employed by sticking onto a subject article (forexample various types of product) itself or a package of the subjectarticles with the aim of protecting these from counterfeiting. Overt andcovert recordings are made on the face on the opposite side to theadhesive layer of these security labels. The manufacturing cost ofsticking a sticker on which overt and covert recordings are made ontothe surface of a subject article or packaging may be lower than that ofmaking overt and covert recordings on the surface of the subject articleitself or the packaging itself. It is desirable that a re-use preventionfunction should be provided so that it is not possible to peel off suchsecurity labels once they have been stuck onto a subject article andthis has been sold in the market, in order to stick the label on againonto a counterfeit product. In order to prevent re-use, for example, theadhesive strength or adhesive capability of the adhesive layer isdetermined such that once the label has been peeled off the adhesiveforce is substantially eliminated. As the adhesive employed in theadhesive layer, there may be mentioned by way of example adhesives ofthe type in which a resin having for example an acrylic resin-based orepoxy-based skeleton is dissolved in a solvent and oxidativepolymerization of the resin constituents is produced by drying thesolvent. Alternatively, in order to prevent re-use, for example one or aplurality of cuts may be provided in the security label such that if anattempt is made to peel off the security label from the subject articleor packaging, the security label is broken or torn. These cuts may beset at will in accordance with the size or shape of the label.

[0097] As the area of such a security label, there may be mentioned byway of example an area of no more than 8 square centimeters. With asecurity label of such a small size, there is little risk of impairingthe external design of the subject article or packaging of the subjectarticle onto which this label is affixed, the manufacturing costs of thelabel can be kept low and the step of sticking it onto the subjectarticle presents no difficulties.

[0098] The security label 200-1 shown in FIG. 14 is a circular stickerof radius for example 15 mm. The portion 200-2 of the letters “EPOON” onthe surface of this security label 200-1 is an overt recording recordedwith color-change ink using for example a liquid-crystal material. Thisovert recording 200-2 is printed by for example a silkscreen methodprinting device. The portion of 200-3 of the letters “Genuine”designated in the Figure with the broken line is a covert recordingprinted with an offset type printing device using for examplefluorescent ink. This covert recording 200-3 employing fluorescent inkcannot be recognized simply with the naked eye under natural light andcan only be recognized when illuminated with ultraviolet rays using“black light”.

[0099] An adhesive layer, not shown, is provided on the back face ofthis security label 200-1. This security label 200-1 is provided withcuts 200-4 directed from the outer edge towards the interior at forexample three locations. The length of these cuts 200-4 is for exampleabout ½ of the radius of this security label 200-1. When an attempt ismade to peel off this security label 200-1 once it has been stuck on tofor example a subject article or the packaging thereof, the securitylabel breaks at the location of the cut 200-4, making re-use impossible.

[0100] The security label 300-1 shown in FIG. 15 is a rectangularsticker of for example height 20 mm, width 40 mm. The portion 300-2 ofthe letters “EPOON” on the surface of this security label 300-1 is anovert recording printed by the silkscreen method using ink containingfor example optical brightness pigment. The ink that is used for theprinting of this covert recording 300-2 contains infra-red absorbingmaterial (for example material whose optical absorbance in thewavelength band of 650 nm or more is particularly higher than that inother wavelength bands). Consequently, when specified light containinginfra-red light is directed on to this covert recording 300-2, reflectedlight having a specified spectral waveform is obtained and the spectralwaveform of this reflected light can be checked using a specialinspection device in which this spectral waveform pattern is previouslystored. This overt recording 300-2 therefore functions as a covertrecording. Also, the portion 300-3 of the letters “Genuine” illustratedby the broken line is a covert recording printed by offset printingusing for example phosphorescent ink. This covert recording 300-3employing phosphorescent ink cannot be recognized simply with the nakedeye under natural light and can only be recognized for example whenilluminated with ultraviolet rays using “black light”. An adhesivelayer, not shown, is provided on the back face of this security label300-1. Cuts 300-4 are provided as shown at the four corner portions ofthis security label 300-1 so as to break when the security label ispeeled off.

[0101] The security label 400-1 shown in FIG. 16 is a diamond-shapedsticker of area for example 6 square centimeters. The portion 400-2 ofthe letters “MAOH” on the surface of this security label 400-1 is anovert recording recorded with a color-change ink containing for exampleliquid-crystal material. This overt recording 400-2 is printed with forexample a silkscreen method printing device. Also, for example astar-shaped design portion 400-3 indicated by broken lines is a covertrecording printed with an offset type printing device using for examplefluorescent ink. This covert recording 400-3 can only be recognized byviewing under illumination with ultraviolet light using for example“black light”. An adhesive layer, not shown, is provided on the backface of this security label 400-1. In addition, cuts 400-4 are providedas shown at two corner portions of this security label 400-1.

[0102] The security label 500-1 shown in FIG. 17 is a star-shapedsticker of for example area 7.5 square centimeters. The portion 500-2 ofthe letters “Long Life” on the surface of this security label 500-1 isan overt recording recorded with a color-change ink containing forexample liquid-crystal material. This overt recording 500-2 is printedwith for example an offset type printing device. Also, the portion 500-3of the letters “E, P, O, O, N” indicated by broken lines is a covertrecording printed with an offset type printing device using for examplefluorescent ink. An adhesive layer, not shown, is provided on the backface of this security label 500-1. In addition, cuts 500-4 are providedas shown at two recessed corner portions of this security label 500-1.

[0103] While embodiments of the present invention have been describedabove, these are given by way of example for description of the presentinvention and it is not intended that the scope of the present inventionshould be restricted solely to these embodiments. The present inventioncan therefore be put into practice in various other modes withoutdeparting from the essence thereof.

[0104] A recorded article according to the present invention may be usedto prevent counterfeiting of a product or to check the genuineness orthereof, by being applied to the product itself, which may be of varioustypes manufactured of various materials such as paper, plastics, metalor wood, or to the product packaging or ancillary articles such asguarantees associated with the product. Also, a security label accordingto the present invention may be utilized for prevention of productcounterfeiting or checking of genuineness, by being stuck onto productsof various types as described above, the packaging of these products orancillary articles associated with these products.

1. A recorded article comprising an overt recording recorded by an overttechnique and a covert recording recorded by a covert technique on thesame recording medium.
 2. The recorded article according to claim 1,wherein said overt recording and said covert recording at leastpartially overlap.
 3. The recorded article according to claim 1, whereinsaid overt recording and said covert recording are of different plandesign.
 4. The recorded article according to claim 1, wherein said overtrecording is formed by superimposing liquid-crystal ink on acolor-change ink.
 5. The recorded article according to claim 1, whereinsaid overt recording and said covert recording are at least partiallysuperimposed.
 6. The recorded article according to claim 5, wherein saidcovert recording is formed by an optical retroreflection layercomprising minute transparent spheres arranged on a transparentreflecting layer.
 7. The recorded article according to claim 1, whereinsaid overt recording and said covert recording are the same in plandesign and are stacked in alignment.
 8. The recorded article accordingto claim 7, wherein said overt recording is formed by superimposingliquid-crystal ink on an underlayer of a specified color, the backgroundregion around said overt recording is formed by superimposing saidliquid-crystal ink on an underlayer of a different color or by directlyemploying an underlayer of said specified color, without superimposingsaid liquid-crystal ink thereon whereby said overt recording is made tofunction also as a covert recording.
 9. The recorded article accordingto claim 7, wherein said overt recording is formed using ink that, inresponse to illumination with specified light, outputs reflected lightor transmitted light having a spectral pattern that matches a specifiedspectral pattern stored beforehand in an inspection device and saidovert recording thereby functions also as a covert recording capable ofbeing checked by said inspection device.
 10. A method of ascertaininggenuineness of a recorded article on which is formed a recording thatfunctions as both an overt recording and covert recording, usingliquid-crystal ink, comprising the steps of: observing said recordedarticle through a clockwise circularly polarized plate; and observingsaid recorded article through an anticlockwise circularly polarizedplate.
 11. A method of ascertaining genuineness of a recorded article onwhich is formed a recording that functions as both an overt recordingand covert recording, using ink that, in response to illumination withspecified light, outputs reflected light or transmitted light having aspectral pattern that matches a specified spectral pattern storedbeforehand in an inspection device, comprising the steps of: obtainingreflected light or transmitted light output from said recorded articleby illuminating said recorded article with specified light; andcomparing said specified spectral pattern stored beforehand in saidinspection device with the spectral pattern of the reflected light ortransmitted light output from said recorded article.
 12. A securitylabel comprising an overt recording formed by an overt technique and acovert recording formed by a covert technique on the surface of the samerecording medium and further comprising an adhesive layer whereby thesecurity label can be stuck onto a subject article or subject articlepackaging.
 13. A security label according to claim 12 wherein said overtrecording is a recording that produces a color change depending on angleof observation by selective reflection of light and said covertrecording is a recording that is capable of being recognized byemploying a specified tool or device.
 14. The security label accordingto claim 13 wherein said overt recording is a recording made using aliquid-crystal material, or is a recording in which a material isemployed obtained by laminating a metallic oxide layer and/or metal anda thin-film mica glass layer and/or silicon oxide.
 15. The securitylabel according to claim 12 further comprising a second covert recordingformed using a material such that the spectral pattern of the reflectedlight or transmitted light in response to illumination with thespecified light matches the specified spectral pattern stored beforehandin the inspection device, on the surface of said same recording medium.16. The security label according to claim 12 wherein said overtrecording is formed using a material such that the spectral pattern ofthe reflected light or transmitted light in response to illuminationwith the specified light matches the specified spectral pattern storedbeforehand in the inspection device, whereby said overt recordingfunctions also as a second covert recording.
 17. The security labelaccording to claim 12 having an area of no more than 8 squarecentimeters.
 18. The security label according to claim 12 having a cutsuch that the security label is broken if an attempt is made to peel thesecurity label off once it has been stuck onto the subject article. 19.A method of manufacturing a security label wherein an overt recording isprinted by an overt technique and a covert recording is formed by acovert technique on the same recording medium and the printing by saidovert technique is silkscreen method printing.